Process of classifying solids



July 17, 1934. H. H. MCKENNA PROCESS OF CLASSIFYING SOLIDS 3Sheets'Sheet 1 Original Filed Nov. 29, 1927 7 INVENTOR .fl/ 12121264ATTORNEY Jufiy 17, 1934. H MCKENNA 1,966,988

PROCESS OF CLASSIFYING SOLIDS Original Filed Nov. 29, 1927 3Sheets-Sheet 2 a in ' m 17, 1934. H. H. MCKENNA 1,966,988

PROCESS OF CLASSIFYING SOLIDS Original Filed Nov. 29, 1927 3Sheets-Sheet 3 NVENTOR jg [111 12 E M %1212a 4 BY 4 1r I I I ATTORNEYPatented July 17, 1934 UNITED A STATES PROCESS OF CLASSIFYING SOLIDSHugh H. McKenna, Los

Angeles, Calif., assignor,

by mesne assignments, to Wonderful Development 00., Inc., Los Angeles,Calif., a corporationof Nevada Original application November 29, 1927,Serial No; 236,439, now Patent No. 1,837,915, dated .December 22, 1931.Divided and this application June 24, 1929, Serial-No. 373,186. RenewedApril 1'7, 1933 5 Claims.

This invention relates to the classifying of mineral particles accordingto specific gravity and consists ofa method of separating the'mineralparticles mainly by means or" controlled air cur- .rents. 7

This application is a division of my prior application, Serial No.236,439, filed Nov. 29,1927, patented Dec. 2 2 '-1931,:No. 1,837,915.

It is an object of this invention to provide a jmethod of classifyingminerals carried in suspension in a current of air by controlling anddirectingthe air current. I t

It is a further object to agitate comminuted material in controlled aircurrents in such a manner as to cause the particlesof the comminutedmaterial to become suspended in the air currents. v

The invention has as :a. further object the treatment of comminutedmaterial suspended in an air current to effect separation of the courseand fine particles and separate classification of the particlesaccording to specific gravity, or crystalline structure. V A furtherobject of the invention is to subject comminuted material to successiveoperations to effect successive deposition of particles of differ entminerals having different specific gravities, even when the differenceis slight.

One form of apparatus capable of carrying out the method forming thesubject matter of the application is shown in the accompanying drawings,in which: a

Fig. -1 is an elevation,

apparatus.

Fig. 2 is a section taken on the line 22. of Fig. 1. e V

Fig. 3 is a section taken on the line 3-3 01 Fig. 1.

V Fig. 4 is a section ta Fig. 1. I

Fig. 5- is a Fig. 1; T s

Referring to the drawings, the numeral 11 designates a shell, the upperend. 12 of whichis conical .and'is provided with an air inlet conduit'13. The lower end 15 is conical and terminates in a gangue discharge16. A conduit 18 for the admission of ground mineral and gangue passesthrough theconduit 13 and, opens inside the shell 11. T

Supportedv in the upper part oithe shell 11 is a breaking device 19which checks the fall of the comminuted material, scatters any lumpswhich may be present, and distributes the material evenlythrough'thecasing. This breaking, de-

partly insection, of the ken on the line4 4 of section taken on theline5-5 of vice consists of an'upperconical screen 20, preferably about 70mesh, and alower conical screen 21, preferably-about 90 mesh, the basesof which are secured together. The lower part .of the lower screen 21 isprovided with an opening 23. An air nozzle-24 extends through theopening 23. The upper part of the nozzle 24 is connected by radial pipes26 to a manifold 28, which has an inlet 29, controlled bya damper 30.Below the breaking device is a conical screen 33 of 80-100 mesh, theapex of which. extends into the lower end of the nozzle'24. The screen33 is mounted on a conical member 34 which may be provided with screenedopenings 35. The lower end of the conical member 34 opens with a conduit38 which extends to the exterior of the shell 11. The space defined bythe screen 33 and the conical member 34 is designated 36. A conicalbafiie 39 is situated between the two conical walls 15 and 34. The space40 between the baflie 39 and the member 34 communicates with a conduit41. which extends to the exterior'of the shell 11.

The conduit 41 extends horizontally from the shell 11 and opensintotheside of one vertical branch of a pipe 38' of inverted U shape. The lowerend of the said branch communicates with a-trap 56, while the lower. endof the other branch of the pipe38' opens into the conduit 38. c

The conduit 38 is'provided with a relief valve which is placed at theend of a pipe 51. This relief valve is pivoted at 52 and is providedwith a weight 53 which" normally holds it in closed position. T

The conduit 38 extends horizontally from the shell 11 and opens into avertical pipe 64, at the lower end of which isa trap 62. The upper endof the pipe 64 is connectedby a horizontal pipe 64' with anothervertical pipe 68, the lower end of which communicates with a trap 63,and the upper end of which leads to an exhaust blower 42. The trap 56is. provided with openings58 controlled by a damper 59, and a largebafiie plate 57 to prevent eddy currents. Avalved opening 60 permitsremoval of material collected in the trap.

Thetraps, 62 and 63 are identical and are provided with openings 66controlled by dampers 67. Valved openings 69 permit collection of thematerialdeposited in the traps. Inclined bafiie plates 70 are locatedimmediately above the traps in the pipes'64 and 68. i I I Theblower isset in operation to reduce the air pressure vin thevarious .connectedpipes and the shell 11. Comminuted material, crushed below 200 mesh, isintroducedthrough the conduitilB.

space between the shell 11 and the screen 20 and drop downward towardthe gangue discharge-16; The stream of material which has passed throughthe screen 20 and has'become partially suspended in the current of airentering through the conduit 13 is concentrated by the screen 21 towardthe opening 23. A current of air, preferably heated, enters the devicethrough the nozzle 24 and spreads over the screen. Two series ofopenings 44 and 45, controlled by dampers 46 and 4'7 admit two streamsof air.' pressure is primarily in the space 36 below the screen 33, thethree streams of air fromthe-noz-' zle 24 and the openings 44 and 45converge toward the screen from different angles; Thisresults in eddycurrents in the space 48 abovethe screen 33, which'cause violentagitation of'the comminuted material. Thisagitationhas'the effect ofthoroughly cleaning the mineral particles of silt and dust and causingeach particle to become suspended in the air current.

Most of the material fine enough to pass through the screen 33 is drawnthrough the screen into the space' 36 and on into the conduit 38.Particles of material too large to pass through the screen, and anyparticles of material that escape the current of air'passing through thescreen are carried into the space between the conical members'15 and 34.A current of air is being drawn'from this space over the upper edge ofthe baflle 39 into the space-40 and the conduit 41. Part of this air isdrawn upwardly through the gangue-discharge 16, 'and'part'is drawn fromabove the screen 33; Due to the inclinationof the walls, the materialisseparated at this point accordingto specific gravity, the heaviermaterial falling down through the discharge opening 16,and'the'lighter-being drawn with the current of air into'th'espa'ce-40andthe conduit 41. v I

This material passes through the conduit 41 into the pipe'38'. Theupward movement of the-air current at this point tends to causedeposition of all thematerial'carried in the air current-into the trap56, located at the lowerend of the vertical branch of the pipe 38'. Thistendency is resisted by acurrent 'of'air entering'the' trap 'throughtheopenings 58 and moving upwardly into the pipe 38. By'adjusting theamount of air entering the trap by means of'the damper '59, the heavierma terial can be caused'to deposit 1:1 the trap, while the lighter 'iscarried through the pipe" 38"" into the conduit 38.

The material drawn'from' the space 36-and that carriedthrough thepipe38' moves along-the conduit 38 until the traps 62 and 63 are reached atwhich"points' further separations according to specific'gravity'takeplace. All materiarhaving a specific gravity lower thanthe'm'ineral'being collected, such as dust, passes out throughtheblower: a It will be seen that the'complete process consi sts'ofagitating the comminuted material by means of interfering," converging'air currents, separatingthe particles of the material according tosize',"and separately classifying the resulting streamsofmaterial-"according 'to=specific vity. j

Specifically, 'the' agitation step consists of di- Any particles Sincethe reduced recting a current of air against the apex of a conicalscreen, and directing a stream of comminuted material at the screen fromabove the airyand directing a plurality of additional air currentsagainst the screen from diiferent angles.

The resulting agitation thoroughly cleans and separates the particles ofthe material. The fine particles, which may be readily and accuratelyclassified in the traps, pass through the screen. The coarser particles;and such material as does not pass through the screen, is directed intoan annular discharge passage, and a current of air is directed upwardlythrough said material, allowingonlyrthexgangue that is heavier than themineral being collected to pass through the discharge-opening.Substantially the same method is involved in the operation of all of thetraps. The stream of air and suspended material is deflected upwardly totend to cause deposition of the suspended material, and a current of airis directed upwardly through the'material to prevent deposition of thelighter portion thereof.

The invention comprehends variations in the process within the scope ofthe appended claims.

Any suitable type of apparatus may be utilized rality of currents of airagainst said screen at different angles thereto, to cause agitation ofsaid material at the confluence of said currents;

2. The process of classifying comminuted material, consistingof reducingthe air pressure in achamberpadmitting a stream of comminuted materialinto the chamber and allowing the same to fallby gravity against aninclined surface, admitting air into the chamber in such a manner as tocreate a current of air moving against the direction of motion of thestream of material to cause'agitation-of the same, directing thematerial through a discharge opening, and admitting a current of airinto the chamber through the said discharge opening to prevent thelighter portion of 'said'material from passing through said opening."

3. In a process of the class described,- the-improvement which consistsof suspending comminuting material in a stream of air, moving the streamof air and suspended material horizontally zontally andthen deflectingit upwardly by means of an exhaustblower, and directing a jet of airupwardly'at an angle through the material at the point'of deflection andagainst the direction of motion thereof to prevent separation of suchmaterial from the stream of air.

5. A processof'separating' and classifying ore comprising pulverizingthe ore bearing rock, introducing the pulverized material into aseparator apparatus, drawing a stream of air through the apparatus,scattering iand'diifusing thema- 15 air of such force and direction asto prevent the separation therefrom of particles within said range ofspecific gravities having certain crystalline structures, whilepermitting the separation of other particles having other crystallinestructures, and separately collecting the material so classified.

HUGH H. MCKENNA.

